Ammunition magazines, and, more particularly, drum magazines, are well known in the art of firearms. An open end, which is the feed portion or feed end, is the portion that interfaces directly with a weapon and is generally attached by way of a feed tower to a drum body. The drum body stores loaded cartridges in a generally spiraled or winding configuration for movement towards the feed tower and feed end. Inside the drum body of some designs, a torsional spring and follower assembly are implemented to guide loaded cartridges towards the feed portion. In use, when one cartridge is expended, the compressed spring releases and pushes the follower and associated ammunition through the winding track and towards the feed end, and the next cartridge is thereby readied. To allow for loading of a drum magazine onto a weapon designed for accepting a stick-type, box magazine, the follower assembly and feed described above provide a kinetic chain for translating torsional force into a linear force when cartridges are moved from the drum body to the feed tower.
In other designs, a compression spring, as opposed to a torsional spring, guides loaded cartridges through a curved track towards a feed portion. In these designs, the track is necessarily limited to a large radius of curvature, resulting in a bulky magazine, as well as an exacerbation of frictional forces due to non-optimal cartridge stacking, and reduction in reliability.
In still other designs, winding of the spring is necessary after loading, meaning the user carries a significant burden with respect to loading and storage. For example, in some designs, after loading, the user must remember to use a main winding key to wind a spring, such as about ten turns, even noting the number of turns as well as remember to not over-wind the spring. Yet, if the user under-winds the spring, the cartridges may not feed correctly, requiring further winding by the user, potentially while in the field. Further, if the user plans to place a loaded drum magazine in storage, the user must remember to wind the spring only partially to prevent setting, and then again remember to fully wind just prior to use. These are just a few examples of the challenges faced by users of these designs.
Prior drum magazines have been manufactured in many different configurations and of different materials. As one example, in currently-available feed towers and drum magazine assemblies, as the magazine approaches the maximum loading capacity, the friction of the cartridges inside the drum does not allow for the spring force to resist the natural tendency of the first cartridge to nose-dive, thus adversely affecting chambering reliability. This diving of the distal tip of a first cartridge may be particularly exacerbated when frictional forces between other cartridges in the magazine and the magazine itself are excessive; that is, the relative strength of the torsional spring relative to the cartridge to be loaded is further reduced. In other examples, friction between the drum magazine and the loaded cartridges can cause jamming or delayed responses as the cartridges are moved through the drum magazine, thus reducing the reliability of the magazine and weapon and adversely affecting the feed rate responsiveness—i.e. the response rate of feeding to the rate of fire.
In still other examples, currently available drum magazines require the use of a “third hand” for loading. Specifically, two hands are required to actually load the magazine, meaning the user must prop the magazine against a wall, table, surface, other firm object, or the user's body, using the user's torso, elbow, leg, etc, to have both hands available for loading. In still other examples, inserting a loaded magazine into a weapon having a closed bolt may cause damage to the cartridges, or prevent the magazine from being inserted correctly, thereby causing misfeeds and/or complete loss or dropping of the magazine from the weapon.
As another example, currently-available magazines exhibit an excessive tolerance in the spacing between the front and rear portions. Although the excessive tolerance is sometimes unintentional, it is often necessary in currently-available designs. For example, and using the .223 Remington cartridge as just one example, manufacturers of currently-available designs must allow for an overall variance in the cartridge length of 0.095 inches, or 2.413 millimeters, which results in less than ideal cartridge travel within the magazine, including excessive friction and indirectly causing excessive noise and rattling while in the field.
Moreover, when a weapon using currently-available designs is fired, the recoil causes the loaded cartridges to hit the front of the magazine. Over time, the front of the magazine begins to develop small craters in the same localized spots. These craters tend to exacerbate the friction between the cartridges and the track, because cartridges must not only overcome inherent friction in the system as designed, but also dig each and every bullet tip of each cartridge out of a corresponding crater. The craters may be even further exacerbated by the use of relatively hard tips, such as in enhanced penetrating or armor-piercing ammunition, as well as the excessive tolerance described above.
Although present magazines and feed towers are functional to varying degrees and reliability, it is desirable to provide a device and/or method with improved reliability, as well as other new and innovative features.